For most people, telling a sizable lie leads to significant guilt and often related behavioral changes when dealing the potential victim of that lie. As it turns out, the same goes for when you tell your grandmother you love the ugly sweater she bought you for Christmas. As cognitive scientist Art Markman, Ph. D, points out, the little lies affect your behavior as well.

He looks at one study in particular—and bear with me, it's a little complicated. In this study, university students went to a research lab and were given a short list of words that they were instructed to use to form sentences. Some participants received lists containing basic words that had no real meaning behind them and some received lists of words relating to honesty. Either way, the research assistant conducting the study purposefully left the participants in the room with nothing to do for about 12 minutes to annoy them. Upon returning, she asked some of them how they were doing. Most said "fine" or, you know, lied as they were actually annoyed. After the initial study, the participants were asked to participate in a second study for which they'd be entered into a $100 raffle. They were also asked to donate a portion of that money back to the person conducting the study—the person many of them told a white lie to—if they won. Participants who were primed to think about honesty and told a white lie were willing to give up more than half their money on average. Everyone else opted to donate about one third of their potential raffle winnings. So what does this all mean? Art Markman explains:

That means that these participants were actually willing to give away more money than they would keep for themselves in order to make up for having told a lie. These findings suggest that white lies aren't simply a form of social grease that we apply to make our social interactions go more smoothly. We really do recognize them as being lies. As a result, we need to be quite careful about how these lies affect our future behavior toward the people we have lied to.

For example, they found that 85% of diners in restaurants admitted to telling white lies when their dining experiences were unsatisfactory (i.e., claiming all was well when it wasn't). However the real interesting finding was that diners who told white lies to cover up their dissatisfactions were then likely to leave bigger tips than those who did not. Why would diners who were less satisfied with their meals and who lied to their server about it leave an even bigger tip as a result? The researchers propose that cognitive dissonance was at play.

While you're not leaving your grandmother a tip for an ugly sweater, that doesn't mean these instances of cognitive dissonance won't translate in other ways. Before you make your next white lie, you should first consider what it could cost you. It might be more than you think.